For a century, the National Park Service has preserved America’s natural and historic treasures. These jewels include Yosemite, Yellowstone and the Bankers Hill apartment of Jonny Wilson and Tyler Render.

“It’s old school, it’s fun,” said Wilson of his L-shaped unit in the Hawthorne Inn, which is listed on the National Register of Historic Places. “It’s almost like living in a museum.”

Built in 1900 as a hotel, the Hawthorne has turn-of-the-century flourishes — redwood bannisters, an atrium capped by skylights — that could dazzle a curator. But the three-story building, converted into 29 apartment units, is owned by history-minded investors instead of the federal government.

“Imagine if we kept this place just as it is for another 50 or 100 years?” said Stephen Parker, one of the owners. “How nice that would be.”

The National Park Service, which marks its 100th anniversary Aug. 25, is a multi-faceted enterprise. Besides 59 national parks, landmarks like Everglades and Yellowstone, it also supervises 122 national monuments. These span the continent, from the Statue of Liberty in New York Harbor to Cabrillo National Monument in Point Loma.

View of the statue of Juan Cabrillo at Cabrillo National Monument with the Coronado Bridge shown in the distance. — Charlie Neuman / San Diego Union-Tribune

It also maintains national battlefields, scenic rivers, natural preserves and trails. Two of the latter wind through San Diego County: The Pacific Crest National Scenic Trail and the Juan Bautista de Anza National Historic Trail.

Finally, there’s the National Register’s 90,000-plus sites of cultural or historic significance, virtually all on private property. Maintained by the park service, the list has 140 county entries: Houses, schools, stagecoach stations, vessels, theaters, ranches and the Hawthorne.

The definition of “national park,” it seems, can be as broad as the Grand Canyon or as narrow as Wilson and Render’s apartment, which barely has room for their two beds.

“Most of the time when people think of the National Park Service they think about the rangers in the Smokey the Bear hat in our national parks,” said Victoria Stauffenberg, a writer in the agency’s Washington, D.C., offices.

“Especially now, during our centennial, we are trying to tell people you probably have a national park in your backyard. San Diego is a classic example.”

Cabrillo’s half acre

There are 412 units in the National Park System, scattered across 28 different categories. Some designations — National Seashores and National Lakeshores, say — are self-explanatory. Others can be mystifying. For instance, what’s the difference between a National Park and a National Monument?

Monuments, Stauffenberg explained, highlight a specific natural, cultural or historic feature. Parks are known for their natural features and sheer expanse.

Her example: “Cabrillo is nowhere near the size of Yellowstone.”

Cabrillo, in fact, was a mere half acre when President Woodrow Wilson created this national monument in 1913, entrusting it to the U.S. Army’s care. The National Park Service, born three years later, inherited Cabrillo in 1933.

That proved temporary — as a wartime measure, the Army closed the monument to the public from 1941 until late 1946.

When the monument was returned to the service, the public returned with a vengeance. Today, about 1 million people annually travel to Point Loma. Thanks to post-war additions, the once-cramped spot is now a spacious 160 acres with ocean-to-mountain views, tide pools, exhibits outlining Juan Rodriguez Cabrillo’s 1542 visit — his expedition was Europe’s introduction to California — and the 19th century lighthouse.

“We call ourselves San Diego’s only national park,” said Ranger Emily Floyd.

Brothers Lucas and Sammy Arden of Chula Vista check out the tide pools near Cabrillo National Monument in 2011. JOHN GASTALDO U-T file photo

To mark the park service’s centennial, Cabrillo will host a party Aug. 25. There will be cake, tours of the lighthouse and a World War II era bunker, an antique vehicle display, ranger talks and tours and other festivities.

One more birthday present: Admission to the monument, normally $10 per vehicle, will be free Aug. 25-28.

.At the Cabrillo National Monument visitors Josh and Becca Mulbey make their way up the spiral staircase. .. — Nelvin C. Cepeda / San Diego Union-Tribune

On a mission

In October 1775, 30 families led by Juan Bautista de Anza set out from Mexico to the San Francisco Presidio. In the eight-month trek they encountered Indian tribes — most of them peaceful — and the occasional settlement. Most of this journey, though, was through rugged, lonely lands.

Today, the Juan Bautista de Anza Historic Trail passes through another kind of wilderness.

“It goes right through Los Angeles,” said Naomi Torres, the trail’s superintendent. “It’s not like the national scenic trails, like the Pacific Crest Trail. It’s pretty rare for people to hike the national historic trails.”

Bart Smith, then, is a rare person. Since 1992, he’s been on a mission to hike all the national trails, scenic and historic. This spring, he completed the 1,200-mile Anza Trail, which begins near Nogales, Ariz., and ends in the Bay Area. He admitted that hiking beside L.A. motorists jangled his nerves, but his toughest days were in the Anza-Borrego Desert.

“That was physically the most challenging section of the entire trail,” said Smith by telephone from New York, where he’s hiking the Washington-Rochambeau Revolutionary Route National Historic Trail.

One of several views of the Anza Borrego desert on the east side of the Pacific Crest Trail, starting at the Penny Pines trailhead. — Julie D. Gerber

Pushing his supplies in a jogging stroller, he hit Coyote Canyon in March. Although temperatures only reached the low 80s, walking across shadeless scree had him worrying about water.

“In the sand,” he said, “you have to work three times as hard to go twice as slow.”

Heat was no issue for the 240 members of Anza’s party, traveling through this desert in December 1775. They were slowed by snow, though, and a Christmas Eve birth. (Both mother and baby, diarists reported, were fine.)

The Pacific Crest National Scenic Trail, a 2,650-mile path that begins south of Campo and ends at the United States’ border with Canada, has more fans. Almost 1,500 people obtained permits to hike the entire trail in 2014, while another 1,187 embarked on segments of at least 500 miles.

Yet the Pacific Crest shares at least one trait with the less popular Anza Trail: The San Diego County segments, especially the five-mile climb from Hauser Canyon to Lake Morena, are among the most challenging.

“The climb out of Hauser Canyon is cited by many hikers as one of the hardest sections of the PCT,” one guide advises, “because it is typically the first day.”

Richard Gere on the roof

If the Hawthorne Inn’s walls could talk, would they tell tales of celebrities and crime? Or would they stress the cool breezes off San Diego Bay, the views of downtown and the working class clientele?

“It’s a great location, right near the bay,” said Michele Mary, 57, a disabled woman who has lived here more than seven years. “The owners are like unbelievable.”

“This place has a cool vibe to it,” said Wilson, 24, a bartender who is helping to launch roommate Tyler Render’s clothing line, Sir Render. “Everybody knows somebody who once lived in this building.”

In its 116 years, the Hawthorne has hosted a small city. Now containing 29 apartments, the Dutch Colonial structure was built as a 31-room hotel. During World War II, the place was popular with the Rosie the Riveters who built B-24 Liberators and PBY Catalinas. Legend has it that later visitors included Muhammad Ali and Sammy Davis Jr. For 1993’s “Mr. Jones,” Richard Gere shot several scenes while balanced precariously on the Hawthorne’s roof.

Parker and a partner bought the place three months ago. He’s heard that a murder or two have been committed here. Others claim the old place is haunted by a female ghost. Still, he raves about the atmosphere.

“It really hasn’t changed,” he said. “It’s still a residence, people stay here long term and they enjoy it. It’s got some nice ocean breezes and people can walk to work, it’s close to the city.”

Since 1982, the Hawthorne has been listed in the National Register. It shares this honor with a wide variety of local spots, some of them prominent — Balboa Park, San Diego State, the

For 130 years, the Hotel del Coronado has dominated San Diego’s skyline. Don Klumpp

Hotel del Coronado, the ferry Berkeley, the bark Star of India. Others are less obvious — the Pythias Lodge, a 1911 Beaux Arts building in downtown San Diego, say, or six Rancho Santa Fe houses designed by Lilian Jenette Rice, an early 20th century architect known for her ecological sensibilities.

None of these are owned or operated by Washington. “We maintain the list of historic properties, but we don’t maintain the properties,” said the park service’s Stauffenberg. “The most we do is provide guidance.”

Some historic properties are eligible for grants and tax breaks, thanks to various federal and state laws. In California, the Mills Act allows local jurisdictions to offer tax relief to owners who preserve or restore historic properties.

To maintain a spot on the list — and those benefits — owners can’t make significant changes to the exterior. When the recent buyers of a San Diego 19th century house on the Register had to replace their rain gutters, they were required to buy new ones crafted from the original material: Redwood.

The Hawthorne could use a fresh coat of paint, but not just any shade will do. “You have to use certain approved colors,” Parker said. “I’m assuming it would have to be anything that would have been used around the turn of the century.”

Yet Parker, who owns several non-historic apartment houses, doesn’t mind the extra effort that it takes to live in the past.

“These places are like museums,” he said, echoing one of his tenants. “You’re really not doing these things for us — it’s really for the people who come later.”